Photo-responsive liquid crystal elastomer logic gates processing optical information

Abstract

The synthesis of stimuli-responsive materials and digital logic operations provides the opportunity to incorporate decision making in soft material systems. Liquid crystal elastomers (LCEs) are attractive materials for such capabilities by virtue of their adaptability and quick actuation to facilitate instantaneous and autonomous decision-making. LCEs are innately thermally responsive, though interesting functionalities of LCEs can be realized by controlling molecular order in the elastomeric network and introducing additives for response to non-thermal stimuli. Herein, carbon black-embedded LCE films with liquid metal-based conductive traces are designed to undergo logic operations based on ultraviolet (UV) barcode inputs. Buffer and NOT switches are laser cut in LCE films with twist-nematic molecular order to enable contact and release of conductive traces. Opposite switching behavior is achieved with selective polymerization of the LCE film in nematic and near-isotropic states. These two types of switches are connected in series and parallel to create basic logic gates that can then be combined into more complex logic operations. UV barcode inputs allow for localized photothermal response resulting from the carbon black particulates absorbing light and emitting heat, thus enabling logic gate computation through the design and assembly of switches. This reversible, repeatable actuation contributes to embedding decision-making capabilities in photo-responsive soft material systems